Lighter wheels, worth it?
Comments
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noodleman wrote:Your bike will feel more lively and responsive through corners. You will also climb hills easier/quicker. Less effort required on constantly changing gradient to maintain a given speed. Less effort needed on braking. There's my opinion.
But is that down to the weight, the rim, the spokes, the bearings, the build or the wearing out of the old components ... or combination of all of them to varying degrees ... ??
By and large, more expensive wheels will perform better than the cheaper counterparts, if they didn't, nobody would bother upgrading.0 -
An eye opening experiment we can all do at home. Take a wheel without a tyre on, hold it by the QR and either spin it yourself or have a friend do it, then try to 'steer' the wheel in a twisting motion as if your arms are the forks.
It's surprising the forces that are exerted.
Now try it again with a tyre fitted, which effectively makes the wheel heavier.0 -
dodgy wrote:An eye opening experiment we can all do at home. Take a wheel without a tyre on, hold it by the QR and either spin it yourself or have a friend do it, then try to 'steer' the wheel in a twisting motion as if your arms are the forks.
It's surprising the forces that are exerted.
Now try it again with a tyre fitted, which effectively makes the wheel heavier.
Congrats on stumbling across a phenomenon that most people learnt about in school physics lessons....
Other than that, I'm not sure what your point is?0 -
markhewitt1978 wrote:You do very much notice lighter wheels on the road. I have a set of RS10 and a set of RS80 and it's great in the spring when I put the RS80 back on. The usual things that they accelerate faster, hold their speed better and give a better ride.
Are two of these attributes of lighter wheels contradictory? Given the flywheel effect which becomes more prevalent with increasing mass, surely a heavier wheel will indeed accelerate slower but retain speed more? Hence, part of the reason why deeper rims are popular on flat courses (overlooking the additional aero benefits)??
I also found the RS80s to give a "nicer ride" than a lot of cheap wheels and wondered if that, in part, was due to the carbon wrap? I also felt that they "accelerated faster" than cheap heavy wheels but Strava segments simply didn't bear this out, perhaps because most climbs lasts longer than a few rotations? My best Strava times are generally recorded on days where I was just 'on one' rather than on a specific two!0 -
As they have been ordered when they arrive ill do a little experiment. Ill go out do a short loop locally that has some climbs and semi rapid descents etc. Come back put the same tyres, tubes an cassette onto the new rims an redo the loop ill slap on the old Garmin as well an see what the difference is back to back. Garmins there for seeing how slow I am an keeping the rest the same hopefully rules out bias. An yes the tyres will be inflated to the same level then I can judge the two on speed and feel.0
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Imposter wrote:dodgy wrote:An eye opening experiment we can all do at home. Take a wheel without a tyre on, hold it by the QR and either spin it yourself or have a friend do it, then try to 'steer' the wheel in a twisting motion as if your arms are the forks.
It's surprising the forces that are exerted.
Now try it again with a tyre fitted, which effectively makes the wheel heavier.
Congrats on stumbling across a phenomenon that most people learnt about in school physics lessons....
Other than that, I'm not sure what your point is?
My point is, some might find it interesting, others like you might use it as an opportunity to ridicule
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Step83 wrote:As they have been ordered when they arrive ill do a little experiment. Ill go out do a short loop locally that has some climbs and semi rapid descents etc. Come back put the same tyres, tubes an cassette onto the new rims an redo the loop ill slap on the old Garmin as well an see what the difference is back to back. Garmins there for seeing how slow I am an keeping the rest the same hopefully rules out bias. An yes the tyres will be inflated to the same level then I can judge the two on speed and feel.
If you are doing the test just to check the 'performance' benefits then you don't have to wait that long. Just do the ride twice now, once with a full water bottle and then again without it*
* For God's sake don't drink the water or we will be arguing the toss for another 30 pages
Now, for a truly scientific test, when you buy the new wheels you will need to ensure that you do the two rides blindfolded. Please post back when that has been completed, or when you can get a signal at the A&E...0 -
Note to self, dont poo between rides, results will be deemed irrelevant I'd like to say I dont carry drink an that I stop at local wineries and sup a local vintage. But thats a load of rubbish we have no wineries here. If its foggy does gulping the air count? 0
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Obviously I'm shallow.
Since I've had the lurgy I've collected but not ridden my new bike and while I currently cannot add an informed comment to the debate my new wheels have shed the same weight as intimated by the OP.
As my new carbon wheels have 40mm sections they look fast even when I'm looking at my bike in my dining room. I'm sure they'll increase the smiles per mile just with the visual look alone. Will I feel faster, undoubtedly but I don't see I'll benefit from being two seconds a mile quicker up a 8% gradient.
However no one has mentioned aerodynamics of a wheel set......“Give a man a fish and feed him for a day. Teach a man to fish and feed him for a lifetime. Teach a man to cycle and he will realize fishing is stupid and boring”
Desmond Tutu0 -
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Bobbinogs wrote:
Are two of these attributes of lighter wheels contradictory? Given the flywheel effect which becomes more prevalent with increasing mass, surely a heavier wheel will indeed accelerate slower but retain speed more? Hence, part of the reason why deeper rims are popular on flat courses (overlooking the additional aero benefits)??
I suspect it might be being able to keep accelerating back to speed on undulating ground, but the effect is that I can hold a speed much easier.I also found the RS80s to give a "nicer ride" than a lot of cheap wheels and wondered if that, in part, was due to the carbon wrap? I also felt that they "accelerated faster" than cheap heavy wheels but Strava segments simply didn't bear this out, perhaps because most climbs lasts longer than a few rotations? My best Strava times are generally recorded on days where I was just 'on one' rather than on a specific two!
It might be the carbon wrap, I don't know. Certainly the difference the wheel makes is tiny in comparison to my own efforts, but time taken doesn't bother me. The RS80's are simply much nicer to ride.0 -
markhewitt1978 wrote:I suspect it might be being able to keep accelerating back to speed on undulating ground, but the effect is that I can hold a speed much easier.
I think what bobbinogs is saying is that the weight of the wheel is incidental to 'holding speed', so it shouldn't make any difference what wheels you are on in those circumstances..
There was a massive (and hugely entertaining) thread on this issue a couple of years ago - well worth digging it up...0 -
FFS! Harden up and grow a pair0
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Svetty wrote:
ok - well assuming you are disagreeing, let's leave it there until you can think of something articulate to say, which moves the debate on...0 -
Imposter wrote:markhewitt1978 wrote:I suspect it might be being able to keep accelerating back to speed on undulating ground, but the effect is that I can hold a speed much easier.
I think what bobbinogs is saying is that the weight of the wheel is incidental to 'holding speed', so it shouldn't make any difference what wheels you are on in those circumstances..
There was a massive (and hugely entertaining) thread on this issue a couple of years ago - well worth digging it up...
I think I was a bit confused about how a lighter wheel could deemed to hold speed well when my understanding of the flywheel effect would normally dictate that a heavier wheel (specifically the rim) would be better at maintaining momentum. However, reading Mark's response, perhaps he didn't mean holding steady momentum like a flywheel, more a case of 'going generally fast due to multiple accelerations on an undulating route' ??
I will have to dig out that old thread, I do seem to recall there were some classic posts with excellent points made, good humour, barbarous personal attacks and a number of opinions based on a complete lack of understanding of the subject in hand. In fact, a prime example of internet forums ;-)0 -
I find this article useful - http://www.rouesartisanales.com/article-15441821.html0
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physics says energy/momentum are conserved, this has been extensively validated, anyone able to prove otherwise will be enjoying a nobel prize and fame for generations
"holding speed" is another way of saying maintaining constant kinetic energy, a massive system (rider+bike) will have greater ke and (in the absence of input energy to overcome losses) its velocity will decrease more slowly than an otherwise identical but less massive system (subject to the same aerodynamic/other losses)
but it will also take more energy to accelerate to a given ke in the first place, i.e. no difference due to mass
it is aerodynamics that makes the difference for cycling...
for road cycling the most obvious real world advantage a lighter system has is in situations with serious climbs
aerodynamic losses going up are minimal as velocity is low (these losses increase exponentially with velocity), two systems able to maintain, say, 350w, and with the same system drag coefficient, will reach the top pretty much inline with their relative system masses
but going down a steep descent the velocity will be much higher, reaching the terminal velocity for the system (at the given power input), the exponential increase in power needed to overcome aerodynamic losses dwarfs the potential energy difference resulting in a much smaller time difference
assuming a climb that the 80kg system scales in 80 minutes, an 81kg system will be a minute behind
on the descent, the 81kg system will not make up that minute, the lighter system will win the racemy bike - faster than god's and twice as shiny0 -
I have wheels from 1020g though to 1900g. All are stiff. The really light ones though may feel nice but in terms of pace are not noticably quicker. My favourite (out of about 20 pairs) set are my wide 50mm deep carbon clinchers weighing in at 1650g -just the right balance of everything. My second favourite set are my 1650g HED belgium tubular rims 28H laced to silver record hubs. You may start seeing a pattern here.
So for me at least lighter is not always better it is just lighter which is fine because I like how a light bike handles. they are not faster though nor would I say heavier wheels hold speed better.
The only thing I notice over a long ride is more aero wheels do help keep my speed up but I also have my aero wheels on my light bikes. The heavier ones (2-8kg heavier) get less aero wheels. So maybe it is not the wheels.
what is helping my up climbs at the moment is the 3kg I lost in hospital. there has to be some benfit from that crash. I cannot save 3kg for wheels.http://www.thecycleclinic.co.uk -wheel building and other stuff.0 -
It depends how steep the hill is. Although I don't know how the op's 400g saving turned into 1kg. Either way those narrow rims look mighty harsh and I bet they weigh a lot more with skewers and rim tape.0
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When you brake, turn, or increase speed, you are accelerating.
F=ma.
Therefore a lower mass means lower forces involved = less effort. Ergo, light wheels = good. (You feel this as a liveliness in your ride, and the 'flickability' of the bike).
This ignores aero benefits though, so you need to think about how and where you're riding. A 10k flat TT is not the same as climbing (and descending) Alpe d'Huez.
I use a light mid-depth carbon wheel as a 'best of both worlds' compromise.
A heavy wheel will, in theory (aero aside) hold it's speed better as it has more momentum. So if you just want to ride flats at a steady 30km/h,(no stops, no bends) a heavier wheel will actually benefit the smoothness of your ride.0 -
Wheels arrived the other day didnt get round to doing anything till last night on them. Numbers below. Both weighed with rim tape but no skewer or cassette, incidentally I removed the stock tape from the new rims an replaced it with my usual electrical tape. Old tape was 42g each rim, new about 6g. One for the weight weenies there.
Old wheels
Front 880g Rear 1133g = 2013g
New Wheels
Front 706g Rear 864g = 1570g
so my maths thats 443g less the bulk of that being the rear wheel. Old rims were 28mm section. new ones 30mm section only had a very quick pootle up the road an back on them so cannot judge but the hubs had a nice sound to them which is always a plus. Look wise I like them real marmite jobbie white rims on a white an grey bike. Least its unique, I'll do some proper testing at the weekend though.0
